RESONANT REFRACTION BY ROUND ISLANDS

Richard E. Meyer

Abstract

Wave trapping by refraction can give rise to resonance of a kind unfamiliar in oceanography. Trapping over realistic seabed topographies is incomplete, but conversely, possesses a mechanism for direct, harmonic excitation from the open sea that is unknown in classical resonance. These phenomena have been studied for the simplest example of an axisymmetric island of typical shape with small seabed slope. Asymptotic analysis has led to simple formulae for resonant frequencies, energy leakage rates and resonant response coefficients. Resonances of extraordinarily large but narrow response have been found.